Presently drugs such as pilocarpine and its various salts are used for the treatment of glaucoma. Although these drugs are useful they generally exhibit side effects such as extreme miosis, spasm of accomodation, night blindness and transient blurried vision. It has now been found that t-butylamino-3-(4-morpholino-1,2,5-thiadiazol-3-yloxy)-2-propanol hydrogen maleate is effective in reducing intraocular pressure both in normal and hypertensive human eyes without the side effects associated with pilocarpine type drugs.